Studios on the Various Filters for Rubber Compounds. Part 1. Physical Properties of Domestic Calcium Carbonate for NR Compounds

고무용(用) 국산(國産) 각종충전제(各種充塡劑)에 관(關)한 연구(硏究) (제1보(第1報)) 고무용(用) 국산(國産) 탄산(炭酸)칼슘의 성능(性能)에 관(關)하여

The influence of various calcium carbonate on the physical properties of natural rubber have teen carries out extensive experiments on compounding. Final evaluation was made through various kinds of physical test-tensile strength, modulus, tear strength and hardnees-including particle size. The results are as follows: 1. Generally, tile tensile strength, modulus and tear strength showed the similar tendency in various calcium carbonate compounding. 2. The maximum volume of general using have been obtained with 150 phr calcium carbonate in $NR-CaCO_3$ compounding. 3. The particle size of domestic calcium carbonate showed $1.0\mu-2.6\mu$.